'E $$\times$$ F' means 'E is the wife of F'
'E $$+$$ F' means 'E is the brother of F'
'E $$\div$$ F' means 'E is the husband of F'
'E $$-$$ F' means 'E is the son of F'
How is P related to R in the expression '$$P \times Q + I - R \div S$$'?

A

Sister

B

Son's wife

C

Wife's sister

D

Wife